1. Field of the Invention
This invention relates to a method of determining whether or not a conductor clamping section of a metal terminal is satisfactorily connected to a wire, and also relates to the metal terminal.
The present application is based on Japanese Patent Application No. Hei. 9-239567, which is incorporated herein by reference.
2. Description of the Related Art
A metal terminal includes an electrical contact section having a predetermined configuration, and a wire connecting section having a conductor clamping section which is connected to a wire by pressure contact. Before conducting the pressure contact, first the wire is cut to a predetermined length, and then an insulating sheath at an end portion of the wire is removed.
When the metal terminal is connected to a conductor of the wire by the pressure contact, the metal terminal must be electrically connected completely to the wire, and must have a holding force which is equivalent to the tensile strength of the wire. That is, the pressure contact of the metal terminal to the wire must be high both in electrical characteristic and mechanical characteristic.
If the pressure contact is not sufficient, a gap may be formed between the conductor clamping section of the metal terminal and the conductor of the wire. In this case, since the holding force by the conductor clamping section is small, the conductor of the wire may easily come off the metal terminal.
At a site of production, for the purpose of quality control, there may be a case in that a conductor clamping section of a metal terminal by which a conductor of a wire is clamped is cut across the axis of the terminal, and from the resultant section the compressibility of the wire with respect to the conductor clamping section is calculated. Based on the compressibility as one yardstick, state of the connection between the metal terminal and the wire is determined.
On the other hand, when the metal terminal is connected to the wire by the pressure contact, wire breakage preventing bellmouths are formed on both end portions of the conductor clamping section in an axial direction of the terminal so as to hem the both end portions. Similar to the above-described site of production, for the purpose of quality control, the width of the bellmouths in the axial direction of the terminal may be periodically measured in order to determine the state of formation of the conductor clamping section.
In the above-described structure, a troublesome operation may be carried out. That is, whenever the state of the connection between the metal terminal and the wire is determined, the conductor clamping section must be cut to examine the compressibility of the wire with respect to the conductor clamping section. If the aforementioned operation must take a long time, the productivity of the manufacture is lowered.
Further, in the dimensional inspection of the bellmouths, since the bellmouths are extremely small, measurement of the dimension of the bellmouths may be troublesome. Therefore, such measurement is liable to occur an error, and similarly to the above-described case, the productivity of the manufacture is lowered. In addition, the connection of the wire is not sufficiently high in reliability.